The present invention relates generally to horizontal directional drill machines. It relates particularly to a pipe retention and cartridge locking system for a horizontal directional drill machine.
A horizontal directional drill machine is a common and well-known machine for installing pipes beneath the ground and generally parallel to the surface. These machines are used in many different applications and are available in a wide range of sizes. Typical applications where a horizontal directional drill machine might be used include the installation of fiber optic cables, electrical cables, gas lines, water systems, or sewer systems. Horizontal directional drill machines are commonly rated in terms of pull-back capacity. Some machines for smaller applications have as little as five thousand pounds of pull-back capacity. Other machines are available with a pull-back capacity of as much as one million pounds.
One alternative to a horizontal directional drill machine is the traditional trencher machine. A trencher machine simply digs a trench into the ground, and after (for example) pipe is laid down in the bottom of the trench, the trench is filled and the pipe is buried. The advantage of a horizontal directional drill machine over a trenching machine is that a pipe can be buried in the ground over long distances without digging a trench. Thus, a horizontal directional drill is particularly desirable when a trench would be difficult or too costly to dig. For example, a horizontal directional drill machine finds particularly advantageous application for installing pipes under roadways, where destruction of the road is expensive and inconvenient to travelers, or under a waterway like a river, where trenching would be impossible.
A unique aspect of a horizontal directional drill machine is the special drill head that is attached to the front end of a pipe to be laid. The drill head has an angled shape which allows the operator to change the direction of the pipe after it has entered the ground. Direction changes are achieved by stopping the pipe and drill head rotation and orienting the drill head at a desired angle. Then, by pushing on the drill pipe without rotating it, the drill head and attached pipe will veer in the desired direction. Thus, by effecting directional changes to pipe travel, a pipe might enter the ground at an angle, travel horizontally over a long distance, and exit the ground at another angle. This ability to change the direction of pipe travel also allows the operator to steer the pipe around underground obstacles like boulders.
A completely drilled pipe length is made up of an assembly of shorter pipe lengths that are attached to each other end to end. As the pipe is drilled through the ground, successive pipe lengths are attached to the preceding pipe assembly to provide additional length. The additional pipe lengths are stored on the drill machine in a cartridge. The bottom pipes in the cartridge feed down through an opening in the bottom of the cartridge and are successively attached to the preceding pipe assembly with the aid of a loader.
Preferably, the cartridge is detachable from the drill machine body. This feature allows a cartridge to be reloaded with new pipe lengths at a place away from the drill machine. Additionally, the drill machine can continue operations after a relatively quick exchange of the empty cartridge for a new, fully loaded cartridge without the delay that would be associated with reloading pipes individually.
Because the bottom of the cartridge is open to allow downward feeding of the pipes when the cartridge is seated in the drill machine, a system is required to obstruct this opening and prevent the pipes from falling through the opening when the cartridge is detached from the drill. Additionally, a system is required to lock the cartridge in place when the cartridge is attached, to prevent unwanted movement of the cartridge. Naturally, systems that are simple and less costly are the most desirable.
It is therefore an object of the invention to provide a system that performs the dual functions of retaining pipe segments within a cartridge when the cartridge is detached, and locking the cartridge to the drill machine when the cartridge is attached.
It is another object of the present invention to provide a system including a bracket assembly that obstructs the bottom opening in a cartridge and prevents pipes from falling through the opening when the cartridge is detached from the drill machine.
It is a further object to provide a bracket assembly which allows the pipes to feed through the bottom opening and lock the cartridge to the drill machine when the cartridge is attached.
According to the invention, a bracket assembly is provided at each end of a cartridge. The bracket assemblies are identical. Each bracket assembly includes opposed side plates which are attached together with a handle which fixedly aligns the side plates with each other. The side plates are mounted within hollow, longitudinal support members of a cartridge. A set of pivot holes extend through the side plates and the longitudinal support members. A pivot pin is installed through the pivot holes and allows the bracket assembly to rotate between a pipe retention position and a locked position.
A set of pipe retention holes extend through a lower portion of the side plates. In the pipe retention position, the lower portion of the side plates extend through open slots in the bottom of the longitudinal support members. A dual purpose removable pin is then installed through the pipe retention holes and extends transversely below the bottom opening of the cartridge, thereby supporting the weight of the pipes.
In the locked position, the dual purpose removable pin is installed through holes in the longitudinal support members, the side plates, and locking flanges that are fixedly attached to the drill, thereby locking the cartridge to the drill. In this position, the bracket assembly is rotated so that the lower portion of the side plates retracts within the hollow portion of the longitudinal support members to prevent interference between the side plates and the loader mechanisms.